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      SUBROUTINE slAMPQ (RA, DA, AMPRMS, RM, DM)

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      A M P Q
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  Convert star RA,Dec from geocentric apparent to mean place

  The mean coordinate system is the post IAU 1976 system,
  loosely called FK5.

  Use of this routine is appropriate when efficiency is important
  and where many star positions are all to be transformed for
  one epoch and equinox.  The star-independent parameters can be
  obtained by calling the slMAPA routine.

  Given:
     RA       d      apparent RA (radians)
     DA       d      apparent Dec (radians)

     AMPRMS   d(21)  star-independent mean-to-apparent parameters:

       (1)      time interval for proper motion (Julian years)
       (2-4)    barycentric position of the Earth (AU)
       (5-7)    heliocentric direction of the Earth (unit vector)
       (8)      (grav rad Sun)*2/(Sun-Earth distance)
       (9-11)   ABV: barycentric Earth velocity in units of c
       (12)     sqrt(1-v**2) where v=modulus(ABV)
       (13-21)  precession/nutation (3,3) matrix

  Returned:
     RM       d      mean RA (radians)
     DM       d      mean Dec (radians)

  References:
     1984 Astronomical Almanac, pp B39-B41.
     (also Lederle & Schwan, Astron. Astrophys. 134,
      1-6, 1984)

  Notes:

  1)  The accuracy is limited by the routine slEVP, called
      by slMAPA, which computes the Earth position and
      velocity using the methods of Stumpff.  The maximum
      error is about 0.3 milliarcsecond.

  2)  Iterative techniques are used for the aberration and
      light deflection corrections so that the routines
      slAMP (or slAMPQ) and slMAP (or slMAPQ) are
      accurate inverses;  even at the edge of the Sun's disc
      the discrepancy is only about 1 nanoarcsecond.

  Called:  slDS2C, slDIMV, slDVDV, slDVN, slDC2S,
           slDA2P

  P.T.Wallace   Starlink   21 June 1993

  Copyright (C) 1995 Rutherford Appleton Laboratory
  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.

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